A new study by an Ohio State University professor and researchers at Duke University has found that fracking — the act of fracturing shale to capture oil and gas — does not inherently contaminate nearby drinking water wells. ’
But poorly constructed wells with leaky casings or faulty cement can cause methane to leech into drinking water, according to the study, published in today’s Proceedings of the National Academy of Sciences.
That means that, as long as a well is built correctly, methane is not likely to move from shale deep beneath the Earth’s surface into a drinking water well, said Thomas Darrah, an assistant professor of geochemistry at Ohio State and the study’s lead author.
“The implication is that future improvements in well integrity will keep methane out of drinking water,” Darrah said.
Darrah and researchers from Duke, Stanford, Dartmouth and the University of Rochester analyzed 133 samples from drinking water wells over the Marcellus and Barnett shale formations. The Marcellus covers much of Pennsylvania and reaches into parts of eastern Ohio. The Barnett is mostly found in Texas.
The researchers found eight clusters of contaminated groundwater wells near shale gas drilling sites — seven in the Marcellus region and one in the Barnett.